7977661 has 4 divisors (see below), whose sum is σ = 8163232. Its totient is φ = 7792092.

The previous prime is 7977653. The next prime is 7977677. The reversal of 7977661 is 1667797.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1667797 = 397 ⋅4201.

It is a cyclic number.

It is not a de Polignac number, because 7977661 - 2³ = 7977653 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (43), and also a Moran number because the ratio is a prime number: 185527 = 7977661 / (7 + 9 + 7 + 7 + 6 + 6 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7977611) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 92721 + ... + 92806.

It is an arithmetic number, because the mean of its divisors is an integer number (2040808).

Almost surely, 2^7977661 is an apocalyptic number.

It is an amenable number.

7977661 is a deficient number, since it is larger than the sum of its proper divisors (185571).

7977661 is a wasteful number, since it uses less digits than its factorization.

7977661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185570.

The product of its digits is 111132, while the sum is 43.

The square root of 7977661 is about 2824.4753495118. The cubic root of 7977661 is about 199.8136681227.

The spelling of 7977661 in words is "seven million, nine hundred seventy-seven thousand, six hundred sixty-one".